The long-term goal of this program is to develop our novel antimicrobial, teixobactin, into a therapeutic for treating a wide range of infections caused by Gram-positive pathogens including Staphylococcus aureus, Streptococcus pneumoniae, Bacillus anthracis, Mycobacterium tuberculosis, Enterococcus faecalis and E. faecium. The goal of this Phase IIB project is to complete preclinical development of teixobactin in preparation for clinical trials. Using our iChip culturing technology, NovoBiotic has been exploiting previously uncultivable bacteria that make up 99% of all microorganisms for production of secondary metabolites. In 2015, NovoBiotic reported the discovery of teixobactin, the first member of a novel class of peptidoglycan synthesis inhibitors. Although teixobactin showed some favorable drug properties, it was found to gelate in serum or phosphate buffered saline, resulting in sporadic adverse effects in animals. Due to this narrow safety window, we decided to focus on a formulation screening program to prevent or significantly reduce this gelation property to minimize or eliminate the adverse effects. After screening over 800 potential vehicles and vehicle combinations, we developed a new formulation of teixobactin, using an FDA-approved vehicle, which reduces gelation in serum, shows no loss in potency against pathogens, is well tolerated in animals while providing blood levels far exceeding the MIC for several hours, and is highly efficacious in two validated mouse models of infection. The other aims of the Phase IIA grant that were not influenced by the formulation studies were fulfilled, such as improving the teixobactin fermentation yields 10-fold, and studying the postantibiotic effect of the compound. The goal of this project is to advance the newly-formulated teixobactin through IND-enabling studies in preparation for clinical trials. This will include: (Aim 1) produce enough compound through fermentation to conduct all IND-enabling studies; (Aim 2) perform FDA-recommended in vitro and in vivo pharmacokinetics (PK) and GLP safety pharmacology studies, as well as a murine PK/PD study; (Aim 3) perform non-GLP and GLP toxicity studies in two species; (Aim 4) perform preformulation studies such as determining the stability, solubility and physicochemical properties of teixobactin as part of establishing the Chemistry Manufacturing and Controls (CMC) parameters. With a successful Phase IIB program, we will have sufficient data to file an IND, and prepare for large-scale manufacturing and clinical trials.